I know similar questions have been asked before, but they all seem to have been resolved by reworking how arguments are passed (i.e. using a list, etc).
However, I have a problem here in that I don't have that option. There is a particular command line program (I am using a Bash shell) to which I must pass a quoted string. It cannot be unquoted, it cannot have a replicated argument, it just has to be either single or double quoted.
command -flag 'foo foo1'
I cannot use command -flag foo foo1, nor can I use command -flag foo -flag foo1. I believe this is an oversight in how the command was programmed to receive input, but I have no control over it.
I am passing arguments as follows:
self.commands = [
self.path,
'-flag1', quoted_argument,
'-flag2', 'test',
...etc...
]
process = subprocess.Popen(self.commands, stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
results = process.communicate(input)
Where quoted_argument is something like 'foo foo1 foo2'.
I have tried escaping the single quote ("\'foo foo1 foo2\'"), but I get no output.
I know this is considered bad practice because it is ambiguous to interpret, but I don't have another option. Any ideas?
The shell breaks command strings into lists. The quotes tell the shell to put multiple words into a single list item. Since you are building the list yourself, you add the words as a single item without the quotes.
These two Popen commands are equivalent
Popen("command -flag 'foo foo1'", shell=True)
Popen(["command", "-flag", "foo foo1"])
EDIT
This answer deals with escaping characters in the shell. If you don't use the shell, you don't add any quotes or escapes, just put in the string itself. There are other issues with skipping the shell, like piping commands, running background jobs, using shell variables and etc. These all can be done in python instead of the shell.